With the increasing use of portable media players, such as MP3 players with video capability, videos are now commonly created for use with these devices. For example, online stores are providing movies, television episodes, and other video content for download to portable media devices. The video content provided for these devices may have video characteristics that are suitable for display on the small display screens of these portable devices.
Another form of video content that is also becoming popular is online video. In particular, many television shows and movies are readily available for download on demand. Furthermore, many users share user-generated videos to the public through various video-sharing websites. Conventionally, these Internet-provided videos are displayed on personal computer (PC) or laptop monitors, where screen sizes are relatively small. Therefore, online video, as well as videos generated for portable media players, typically have lower resolution.
In addition to having lower resolution, user-generated videos on the Internet are often created by amateurs who are unfamiliar with or unable to use professional techniques in video-generation. For example, user-generated videos may be filmed on hand-held video cameras. Thus, due to the shaking camera, the frame-by-frame video may change even for unchanging backgrounds. For a given data rate, this causes a disproportionate amount of compressed video data to be used on backgrounds and other still images. For this and other reasons, user-generated content often suffers not only from low resolution, but also from artifacts. Artifacts are referred to herein as visually displeasing portions in a display that are caused by video compression. Common artifacts include blocking artifacts and mosquito noise. Blocking artifacts refer to the blocky appearance of a low resolution video that is typically seen on areas of less detail in the image. Mosquito noise is a ringing effect, caused by truncating high-frequency luminance and/or chrominance coefficients, typically seen around sharp edges in the video.
With improvements in technology, and in particular networking, Internet content and portable media player content may be displayed on other devices, such as on television screens. However, these other devices may have larger screens, and therefore higher resolution, than that of the video content provided by the Internet or portable media players. Therefore, when videos with lower resolution, and in some cases with compression artifacts, are blown up to a larger size, the picture quality may become unacceptably poor, creating an unpleasant viewing experience for a user.
Furthermore, processing techniques performed by large-screen display devices when preparing a video signal for display on the device may worsen the presentation of low-resolution video. One such processing technique performed by display devices is deinterlacing, a process that changes the way that pixels are drawn on a screen. Videos are displayed by a display device by drawing successive images at fast enough rate (e.g., 50 frames per second). Typically, a display presents these images pixel by pixel using either a progressive or interlaced scan. A progressive scan draws out each pixel in an image from the top of the screen to the bottom. Thus, after each scan, a progressive display displays an entire frame. An interlaced scan, on the other hand, draws out the odd pixel lines in an image. Then, at the next time instant, the even pixel lines are drawn out. An interlaced scan, therefore, creates a video by alternating between displaying the odd lines and displaying the even lines of successive images. These half-resolution images are called fields.
Currently, many display devices (e.g., some digital televisions, liquid crystal displays (LCDs), etc.) are progressive displays. However, video transmission standards, such as television broadcast standards, commonly use interlacing. Therefore, these display devices often include deinterlacing circuitry for converting interlaced videos to progressive videos. There are several different deinterlacing techniques employed by digital display devices. These techniques attempt to display an interlaced video with the highest possible visual quality. Thus, to effectively display television broadcasts and other interlaced videos, the deinterlacing circuitry in televisions and other display devices are becoming increasingly complex and sophisticated.
In general, because of these deinterlacing and other new, sophisticated techniques for effectively processing higher-resolution video signals, viewers have come to expect vivid and high-quality images on their television sets. In particular, these techniques are being incorporated into regularly available television sets for displaying large images with higher brightness, contrast, and resolution. However, these complex processing techniques may not be effective when performed on low-resolution, and possibly low-quality, videos, such as content from the Internet or portable media players. In fact, these techniques may worsen the presentation of low-resolution videos. Therefore, there is currently no effective way to present both higher-resolution video content, such as television broadcasts, and low-resolution video content, such as Internet content, on a large-screen device. Thus, it would be desirable to improve the visual quality of low-resolution video on large-screen displays.